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s390/mm: convert to the generic get_user_pages_fast code

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Define the gup_fast_permitted to check against the asce_limit of the
mm attached to the current task, then replace the s390 specific gup
code with the generic implementation in mm/gup.c.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2019-04-23 10:53:21 +02:00
parent d1874a0c28
commit 1a42010cdc
4 changed files with 14 additions and 292 deletions
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1
arch/s390/Kconfig
View File

@ -149,6 +149,7 @@ config S390
select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_TRACER
select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS select HAVE_GCC_PLUGINS
select HAVE_GENERIC_GUP
select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_GZIP select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZ4 select HAVE_KERNEL_LZ4

12
arch/s390/include/asm/pgtable.h
View File

@ -1265,6 +1265,18 @@ static inline pte_t *pte_offset(pmd_t *pmd, unsigned long address)
#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address) #define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
#define pte_unmap(pte) do { } while (0) #define pte_unmap(pte) do { } while (0)
static inline bool gup_fast_permitted(unsigned long start, int nr_pages)
{
unsigned long len, end;
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
if (end < start)
return false;
return end <= current->mm->context.asce_limit;
}
#define gup_fast_permitted gup_fast_permitted
#define pfn_pte(pfn,pgprot) mk_pte_phys(__pa((pfn) << PAGE_SHIFT),(pgprot)) #define pfn_pte(pfn,pgprot) mk_pte_phys(__pa((pfn) << PAGE_SHIFT),(pgprot))
#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT) #define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
#define pte_page(x) pfn_to_page(pte_pfn(x)) #define pte_page(x) pfn_to_page(pte_pfn(x))

2
arch/s390/mm/Makefile
View File

@ -4,7 +4,7 @@
# #
obj-y := init.o fault.o extmem.o mmap.o vmem.o maccess.o obj-y := init.o fault.o extmem.o mmap.o vmem.o maccess.o
obj-y += page-states.o gup.o pageattr.o pgtable.o pgalloc.o obj-y += page-states.o pageattr.o pgtable.o pgalloc.o
obj-$(CONFIG_CMM) += cmm.o obj-$(CONFIG_CMM) += cmm.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o

291
arch/s390/mm/gup.c
View File

@ -1,291 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Lockless get_user_pages_fast for s390
*
* Copyright IBM Corp. 2010
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/vmstat.h>
#include <linux/pagemap.h>
#include <linux/rwsem.h>
#include <asm/pgtable.h>
/*
* The performance critical leaf functions are made noinline otherwise gcc
* inlines everything into a single function which results in too much
* register pressure.
*/
static inline int gup_pte_range(pmd_t pmd, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
struct page *head, *page;
unsigned long mask;
pte_t *ptep, pte;
mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
ptep = pte_offset_map(&pmd, addr);
do {
pte = *ptep;
barrier();
/* Similar to the PMD case, NUMA hinting must take slow path */
if (pte_protnone(pte))
return 0;
if ((pte_val(pte) & mask) != 0)
return 0;
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
head = compound_head(page);
if (!page_cache_get_speculative(head))
return 0;
if (unlikely(pte_val(pte) != pte_val(*ptep))) {
put_page(head);
return 0;
}
VM_BUG_ON_PAGE(compound_head(page) != head, page);
pages[*nr] = page;
(*nr)++;
} while (ptep++, addr += PAGE_SIZE, addr != end);
return 1;
}
static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
struct page *head, *page;
unsigned long mask;
int refs;
mask = (write ? _SEGMENT_ENTRY_PROTECT : 0) | _SEGMENT_ENTRY_INVALID;
if ((pmd_val(pmd) & mask) != 0)
return 0;
VM_BUG_ON(!pfn_valid(pmd_val(pmd) >> PAGE_SHIFT));
refs = 0;
head = pmd_page(pmd);
page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
do {
VM_BUG_ON(compound_head(page) != head);
pages[*nr] = page;
(*nr)++;
page++;
refs++;
} while (addr += PAGE_SIZE, addr != end);
if (!page_cache_add_speculative(head, refs)) {
*nr -= refs;
return 0;
}
if (unlikely(pmd_val(pmd) != pmd_val(*pmdp))) {
*nr -= refs;
while (refs--)
put_page(head);
return 0;
}
return 1;
}
static inline int gup_pmd_range(pud_t pud, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
unsigned long next;
pmd_t *pmdp, pmd;
pmdp = pmd_offset(&pud, addr);
do {
pmd = *pmdp;
barrier();
next = pmd_addr_end(addr, end);
if (pmd_none(pmd))
return 0;
if (unlikely(pmd_large(pmd))) {
/*
* NUMA hinting faults need to be handled in the GUP
* slowpath for accounting purposes and so that they
* can be serialised against THP migration.
*/
if (pmd_protnone(pmd))
return 0;
if (!gup_huge_pmd(pmdp, pmd, addr, next,
write, pages, nr))
return 0;
} else if (!gup_pte_range(pmd, addr, next,
write, pages, nr))
return 0;
} while (pmdp++, addr = next, addr != end);
return 1;
}
static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
struct page *head, *page;
unsigned long mask;
int refs;
mask = (write ? _REGION_ENTRY_PROTECT : 0) | _REGION_ENTRY_INVALID;
if ((pud_val(pud) & mask) != 0)
return 0;
VM_BUG_ON(!pfn_valid(pud_pfn(pud)));
refs = 0;
head = pud_page(pud);
page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
do {
VM_BUG_ON_PAGE(compound_head(page) != head, page);
pages[*nr] = page;
(*nr)++;
page++;
refs++;
} while (addr += PAGE_SIZE, addr != end);
if (!page_cache_add_speculative(head, refs)) {
*nr -= refs;
return 0;
}
if (unlikely(pud_val(pud) != pud_val(*pudp))) {
*nr -= refs;
while (refs--)
put_page(head);
return 0;
}
return 1;
}
static inline int gup_pud_range(p4d_t p4d, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
unsigned long next;
pud_t *pudp, pud;
pudp = pud_offset(&p4d, addr);
do {
pud = *pudp;
barrier();
next = pud_addr_end(addr, end);
if (pud_none(pud))
return 0;
if (unlikely(pud_large(pud))) {
if (!gup_huge_pud(pudp, pud, addr, next, write, pages,
nr))
return 0;
} else if (!gup_pmd_range(pud, addr, next, write, pages,
nr))
return 0;
} while (pudp++, addr = next, addr != end);
return 1;
}
static inline int gup_p4d_range(pgd_t pgd, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
unsigned long next;
p4d_t *p4dp, p4d;
p4dp = p4d_offset(&pgd, addr);
do {
p4d = *p4dp;
barrier();
next = p4d_addr_end(addr, end);
if (p4d_none(p4d))
return 0;
if (!gup_pud_range(p4d, addr, next, write, pages, nr))
return 0;
} while (p4dp++, addr = next, addr != end);
return 1;
}
/*
* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
* back to the regular GUP.
* Note a difference with get_user_pages_fast: this always returns the
* number of pages pinned, 0 if no pages were pinned.
*/
int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
{
struct mm_struct *mm = current->mm;
unsigned long addr, len, end;
unsigned long next, flags;
pgd_t *pgdp, pgd;
int nr = 0;
start &= PAGE_MASK;
addr = start;
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
if ((end <= start) || (end > mm->context.asce_limit))
return 0;
/*
* local_irq_save() doesn't prevent pagetable teardown, but does
* prevent the pagetables from being freed on s390.
*
* So long as we atomically load page table pointers versus teardown,
* we can follow the address down to the the page and take a ref on it.
*/
local_irq_save(flags);
pgdp = pgd_offset(mm, addr);
do {
pgd = *pgdp;
barrier();
next = pgd_addr_end(addr, end);
if (pgd_none(pgd))
break;
if (!gup_p4d_range(pgd, addr, next, write, pages, &nr))
break;
} while (pgdp++, addr = next, addr != end);
local_irq_restore(flags);
return nr;
}
/**
* get_user_pages_fast() - pin user pages in memory
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @write: whether pages will be written to
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
*
* Attempt to pin user pages in memory without taking mm->mmap_sem.
* If not successful, it will fall back to taking the lock and
* calling get_user_pages().
*
* Returns number of pages pinned. This may be fewer than the number
* requested. If nr_pages is 0 or negative, returns 0. If no pages
* were pinned, returns -errno.
*/
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
{
int nr, ret;
might_sleep();
start &= PAGE_MASK;
nr = __get_user_pages_fast(start, nr_pages, write, pages);
if (nr == nr_pages)
return nr;
/* Try to get the remaining pages with get_user_pages */
start += nr << PAGE_SHIFT;
pages += nr;
ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0)
ret = (ret < 0) ? nr : ret + nr;
return ret;
}